Supramolecular systems of 5-(4-nitro phenyl)-10,15,20-tris-phenyl porphyrin with cyclodextrins

In neutral phosphate buffer solutions of pH 7. 0, the inclusive complexation of 5-(4-nitro phenyl)-10, 15,20-tris-phenyl porphyrin (o-NTPP) with alpha-cyclodextrin (alpha-CD), beta-CD, heptakis (2, 3, 6-tri-O-methyl) -beta-CD (TM-beta-CD), carboxymethyl-beta-CD (CM-beta-CD) and gamma-CD has been examined by means of UV-vis, fluorescence spectrometry and (HNMR)-H-1 technique. The formation of inclusion complexes has been confirmed on the basis of changes of spectral properties. The o-NTPP forms 1:2 inclusion complexes with TM-beta-CD and 1:1 inclusion complexes with the other three cyclodextrins. The formation constants (k) for the inclusion complexes have been estimated from the changes of absorbance and fluorescence intensity in neutral phosphate buffer solutions. It is shown that TM-beta-CD exhibits the strongest inclusive ability in the five cyclodextrins.